(1) Field of the Invention
The present invention relates to brushes for use in electrolytic treatment, and more particularly to brushes suited for plating, polishing, etching, anodic oxidation or electrolytic pigmentation.
(2) Description of the Prior Art
Generally, what is known as brush plating which employs a pencil type electrode is used in plating workpieces which cannot be immersed in a plating bath or in plating only part of workpieces.
Further, since the device is in the form of a brush, multi-layer plating can be applied to a workpiece by repeatedly running the brush over its surfaces. Thus, brush plating is applicable also to those workpieces which require plating layers.
The brush used in such technique comprises an electrode fixed to a brush body and connected to the positive terminal of a D.C. source. A workpiece is connected to the negative terminal. An appropriate plating solution is applied to the electrode directly or through a liquid retaining material. In this state, direct current is applied to the electrode which is run lightly over workpiece surfaces. The conventional technique has the following disadvantages.
In carrying out a desired plating treatment, the electrode may be formed of the same material as the plating such that, for example, a copper electrode is used for effecting copper plating and a silver electrode for silver plating. Thus, different brushes with electrodes formed of metals corresponding to the plating metals are made available. It is very expensive to prepare and use the brushes having different types of electrodes.
An insoluble electrode such as of stainless steel or baked carbon may be used, but here again a plating solution corresponding to the electrode must be applied thereto. Even where a plurality of brushes having the same type of electrodes are available for use, the brushes used with a particular type of plating solution cannot be used with a different plating solution without completely removing the earlier solution. This cleaning operation is very troublesome, and therefore many brushes must be made available for exclusive use with respective plating solutions (plating metals).
Where an external D.C. source is used as the power source, many lead wires run from the plurality of brushes across the site of operation, which present obstacles to the operation. If only one lead wire is used for one brush and then for another, the connecting operation will be too troublesome.